Field of the Invention
The present invention relates to an exposure apparatus and a method of manufacturing an article.
Description of the Related Art
When manufacturing a semiconductor device using photolithography, an exposure apparatus that projects the pattern of a mask (reticle) to a substrate by a projection optical system and transfers the pattern is used. The recent mainstream is a scan-type exposure apparatus (scanner) that continuously transfers the pattern of a mask to a substrate while synchronously scanning the mask and the substrate.
In the exposure apparatus, out of light passed (transmitted) through the mask, light reflected by an optical element in the projection optical system and then reflected by the mask again is called flare light (projection system flare light). In the scan-type exposure apparatus, if flare light reaches a region other than an exposure region on the substrate, a light amount distribution is formed in adjacent shot regions (in the scanning direction or a direction perpendicular to the scanning direction) to deteriorate the imaging characteristic. Japanese Patent Laid-Open No. 2008-222222 proposes an exposure apparatus including a projection optical system provided with an aperture stop configured to block flare light.
In the scan-type exposure apparatus, if the aperture stop is provided with the projection optical system as in the related art, flare light that reaches adjacent shot regions adjacent in the direction perpendicular to the scanning direction can be blocked. However, since the exposure slit has a width in the scanning direction, flare light that reaches shot regions adjacent in scanning direction cannot completely be blocked. Hence, in the scan-type exposure apparatus, it is impossible to sufficiently suppress, by the prior art, deterioration of the imaging characteristic cased by flare light.